U.S. Pat. No. 5,999,417 (the '417 patent), the entire teachings in which are incorporated herein by reference, discloses a power converter comprising a power source and a primary transformer winding circuit connected to the source. A secondary transformer winding circuit has at least one secondary winding coupled to a primary winding. Plural controlled rectifiers, such as voltage controlled field effect transistors, each having a parallel uncontrolled rectifier, are turned on and off in synchronization with the voltage waveform across a primary winding to provide an output. Each primary winding has a voltage waveform with a fixed duty cycle and transition times which are short relative to the on-state and off-state times of the controlled rectifiers. A regulator regulates the output while the fixed duty cycle is maintained.